The given triangle is a right triangle right angled at angle C. For angle B the adjacent side is BC ,the side opposite to angle B is AC while AB is hypotenuse. Sin of any angle is ratio of opposite and hypotenuse.
Sin[tex] \frac{opposite}{hypotenuse} [/tex]
The opposite in the figure is 24 and hypotenuse is 25
Substituting the values of opposite and hypotenuse from figure we have:
Sin B=[tex] \frac{24}{25} [/tex]
